Morris Minor Owners Club

I want to order some wiring for Albert but I need to know what rating is appropriate for the headlights and indicators? The thing is the classic wiring company i have just looked at has a limited supply of colour codes for 17A cable and far more for 8.75A.

8.75 amp will be fine for the indicators and headlights.
Current (A) = Watts (W)/Volts (V)

Example 2x21W Indicator bulbs totals 42Watts/12V = 3.5 Amps
2X 55W Headlights = 120W Total / 12V = 10 Amps

Cheers matey!

ohms law I hear you say and no not sherlock

So - from that example above - the 8.5 amp cable is NOT suitable for supplying the headlamps, where the single wire supply normally runs down to the front of the car and then splits to each lamp. You MUST use the heavier 17 amp cable at least up to the split point. Too small cable causes voltage drop (= dim lights) and can of course overheat and eventually perhaps catch fire!

Ooops, yes indeed. For the main headlight feed before it splits to individual lamps, use 17 amp cable. Sorry folks my bad.

It's OK BMC, I only need to make up the individual looms that go from the engine bay to each lamp.

Hello all,

better to have too large a cable than too small, but ensure that the connectors used are also suited to the cable size.

Jtd75, slight correction, that is not ohm's law (V=I x R) but the basic formula for D.C. power.

Alec

better to have too large a cable than too small

But that's the problem you see. I can't find the correct colour wire in the larger size so I was checking the smaller was up to the job.

Hello Peetee,

you could try:- http://www.vehicle-wiring-products.eu/V ... mepage.php

they have the blue\white and blue\red in 17.5 amp size.
Of course you can run two wires of a smaller size together and connect them in a common terminal, untidy, but perfectly sound practice.

Alec

those were the people I tried and it was the green/red and the blue/white I couldn't find.

Hello Peetee,

you need to look at the thin wall cable for blue\white, but you shouldn't need 17.5 amp for green\red which, if my memory is correct is an indicator feed?

Alec

Hi Alec I know its not true but you and I know what he means I was just trying to point out about the various formulars. Its not as easy as just plugging something in and hope it works

Peetee wrote:

better to have too large a cable than too small

But that's the problem you see. I can't find the correct colour wire in the larger size so I was checking the smaller was up to the job.

If originality isn't an issue you could try doubling up on smaller wiring, just make sure you have the same amount of wire cross section.

-GRant F.